POP three-dimensional stacking interconnection substrate and manufacturing method thereof

Abstract

The invention discloses a POP three-dimensional stacked interconnection substrate and a manufacturing method thereof, belongs to the technical field of printed circuits, improves the structural design of a suspended lead, provides a novel suspended lead manufacturing process, calculates the thickness of the whole substrate product by utilizing an early-stage lamination design scheme and combining with the thickness tolerance of each layer of material, and improves the thickness of the whole substrate product under the condition that the thickness of the substrate is known. According to the method, redundant base materials below the leads and among the leads are removed through the method of combining the cutting depth of mechanical depth control and laser etching, the machining process of the suspended lead printed substrate is reduced compared with the original technological process through the method of combining mechanical depth control milling and laser etching, and the operation efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of printed circuits, and in particular relates to a POP three-dimensional stacked interconnection substrate and a manufacturing method thereof. Background Art

[0002] Conventional suspended leads are processed by locally filling them with resist material. Resist material needs to be filled at specified locations when the printed circuit boards are laminated to prevent the prepreg from covering the suspended area during the lamination process. However, in actual processing, the width of the suspended area is only 1 mm, and the resist material can only be filled manually. The operation efficiency is low and there is a risk of misalignment, resulting in abnormal product quality.

[0003] In the field of electronic manufacturing, the precise processing of suspended leads is one of the key links to ensure the performance and reliability of circuit boards. In the traditional production process of suspended leads, in order to prevent the semi-cured sheet glue (usually a pre-impregnated epoxy resin or other polymer material used for interlayer bonding and insulation) from flowing into and covering the lead area designed to be suspended during the interlayer lamination of the printed circuit board, the industry generally uses glue blocking materials for local filling. This glue blocking material has good barrier properties and can effectively prevent glue penetration while maintaining the integrity of the electrical connection.

[0004] However, this process faces many challenges in actual operation. In particular, when the width of the suspended area is reduced to only 1 mm, the process of manually filling the glue blocking material becomes extremely difficult. First, due to the small operating space, workers need extremely high precision and patience to ensure that the glue blocking material is accurately filled into the target position, which not only greatly reduces production efficiency, but also increases labor costs. Secondly, the problem of alignment offset that is difficult to avoid in manual operation has become a major hidden danger affecting product quality. Even for the most skilled operators, it is difficult to guarantee perfect alignment every time on such a small scale. Once the filling position of the glue blocking material deviates, it may cause the semi-cured sheet glue to accidentally cover the suspended area, which in turn causes serious consequences such as circuit short circuit, poor signal transmission or unstable mechanical structure, which directly affects the final performance and reliability of the product.

[0005] In addition, the manual filling process is also difficult to control the amount and distribution uniformity of the glue blocking material. Too much glue blocking may lead to unnecessary material waste and increase the thickness of the circuit board, while too little glue blocking may not effectively block the glue, which also causes quality problems. Therefore, this manual operation method is not only inefficient, but also difficult to control quality, and it is difficult to meet the high precision, high efficiency and high quality requirements of modern electronic products. Summary of the invention

[0006] The present invention provides a POP three-dimensional stacked interconnect substrate and a manufacturing method thereof, which solves the problem that the width of the suspended area is only 1 mm, and the glue blocking material can only be filled manually, the operation efficiency is low and there is a risk of alignment offset, resulting in abnormal product quality.

[0007] To achieve the above object, the present invention provides the following technical solutions: A method for manufacturing a POP three-dimensional stacked interconnect substrate, comprising: Use epoxy glass cloth laminates to design the stack-up, and perform sheet cutting and sheet mapping for each layer; Performing inner layer etching on the thin film, and laminating each layer of the thin film to obtain a laminated substrate; Performing drilling and hole metallization operations on the substrate to obtain metallized holes; Perform pattern transfer and pattern electroplating operations on substrates; Perform alkaline etching and depth control on the substrate; Control the laser cutting and degumming operations of substrates after deep processing; Solder mask coating is applied on the surface of the top and bottom layers of the substrate according to the design layout, followed by chemical nickel-gold deposition, and finally external processing to obtain a POP three-dimensional stacked interconnect substrate. Preferably, the specific steps of thin slice mapping are: Clean and roughen the surface of the sheet by sandblasting or chemical micro-etching; Remove the transfer medium from the lower carrier, place the transfer medium and the printed board at the contact part of the guide line, keep them in full contact, and use the squeezing roller to fix the transfer medium on the printed board. Before fixing, use the positioning guide line to align the position of the transfer medium and the printed board; Select the negative film with the corresponding pattern and attach it to the front and back of the sheet, and use an exposure machine to perform light curing on the transfer medium; After peeling off the negative film on the top and bottom layers of the sheet and letting it stand for a period of time, the photosensitive adhesive solidified on the surface is decomposed according to the areas divided by the negative film pattern and cleaned.

[0008] Preferably, the steps of inner layer etching are specifically as follows: Etch the copper surface without anti-corrosion layer protection to make inner conductive pattern; Remove the dry resist film from the non-effective pattern area on the surface of the thin film.

[0009] Preferably, the specific steps of the lamination operation are: Cut the prepreg into individual pieces and process the positioning holes in a clean and dust-free environment; The inner layer sheet that has been completed with circuit pattern production is blackened to increase the bonding strength between the inner layers of the board after lamination; Use hot melt machine or riveting machine to complete pre-stack-up according to corresponding stacking requirements; Carry out lamination processing according to the requirements of pressed lamination based on product types; The stacked pressing molds are transported to the vacuum laminator through a conveying device; Retrieve the corresponding pressing program to complete the pressing process.

[0010] Preferably, the specific operation steps of drilling are: Process positioning holes on multi-layer boards, check the overlap of inner layer patterns, measure expansion and contraction values, and identify and mark board directions; Fix the multilayer board to the CNC drilling machine table with pins at the locating holes; Read the NC drilling file into the NC drilling machine to drill holes on the multilayer board The CNC milling file is read into the CNC milling machine to perform shape processing on the substrate.

[0011] Preferably, the specific steps of the hole metallization operation are: Use a deburring brush to remove burrs at the hole, oxide layer on the board surface, organic pollutants and other impurities, and roughen the surface to enhance the bonding strength between the board surface and the chemical copper layer; A layer of copper film is deposited on the hole wall of the printed circuit board using chemical plating technology to achieve metallization of the hole wall surface and make the inner layer of each network conductive; Electroplating a dense copper layer on the printed circuit board after chemical copper deposition provides good conductivity and sufficient strength for the metallized holes of the printed circuit board; Clean and dry the printed circuit board after primary electroplating.

[0012] Preferably, the specific steps of alkaline etching are: Remove the anti-plating dry film from the non-effective pattern area on the surface of the substrate; Etch the copper surface without anti-corrosion layer protection to make the outer conductive pattern; Remove the tin protective layer on the conductive circuit.

[0013] Preferably, the steps of controlling the deep processing are specifically as follows: Make a special base plate for high-precision depth control; Before depth control processing, the CNC milling machine work table is measured and calibrated, and a high-precision depth control special base plate is used to ensure that the table surface flatness is controlled within ±30μm before processing the product; The whole board is milled and processed into a single board, and then the non-metallized holes in the single board are used for positioning and installation, and the bottom substrate of the hanging lead is grooved and depth-controlled and thinned.

[0014] Preferably, the steps of applying solder resist coating on the surface of the top layer and the bottom layer of the substrate according to the design layout are specifically as follows: Make solder mask pattern printing template negative film; Place the interconnect substrate in the relative size position of the screen printer through the guide line and align it perfectly; The solder mask ink is printed on the substrate surface through the screen by mechanical pressure. Position and fix the prepared printed film to the substrate through the positioning guide holes around the substrate, keep them in full contact, and use an exposure machine to perform photocuring on the solder resist medium; The exposed substrate with the solder mask is placed in a solder mask developer for development, and the unexposed solder mask layer shielded by the film is removed; And perform curing according to the curing parameters of the solder resist material.

[0015] A POP three-dimensional stacked interconnect substrate is manufactured based on the manufacturing method of the POP three-dimensional stacked interconnect substrate, wherein 0.1-0.2 mm of epoxy base material is retained under the copper lead, and the base material on both sides of the suspended lead is completely removed.

[0016] Compared with the prior art, the present invention has the following beneficial effects: the present invention provides a method for manufacturing a POP three-dimensional stacked interconnect substrate, improves the design of the suspended lead structure, provides a new suspended lead manufacturing process, utilizes the previous stacking design plan, combines the thickness tolerance of each layer of material, calculates the thickness of the entire substrate product, and when the thickness of the substrate is known, removes excess substrate under and between the leads by combining the depth of the cutter with mechanically controlled depth and laser etching. By combining mechanically controlled depth milling and laser etching, the processing flow of the suspended lead printed substrate is reduced compared to the original process flow, thereby improving operating efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a flow chart of a method for manufacturing a POP three-dimensional stacked interconnect substrate according to the present invention; Figure 2 This is a diagram of the stacked structure of an embodiment of the present invention; Figure 3 This is a schematic diagram of drilling and stacking of POP three-dimensional interconnected substrates according to an embodiment of the present invention; Figure 4 This is a schematic diagram of a high-precision depth-controlled single-board positioning structure according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the depth control table structure according to an embodiment of the present invention; Figure 6 This is a depth control effect diagram of the product of the present invention; Figure 7 It is a front view of the suspension lead of the present invention; Figure 8 It is a back view of the suspension lead of the present invention; In the figure: 1-CNC drilling machine workbench, 2-pad, 3-positioning hole, 4-cover plate, 5-multilayer board, 6-template, 7-pin, 8-suspended lead printed circuit board, 9-high-precision depth control special base plate, 10-bakelite board, 11-equipment table, 12-depth control groove, 13-metallized positioning hole in the board. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0021] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0022] For printed circuit boards using traditional processing technology, there are copper wires, epoxy glass fiber cloth, potting glue and other materials during the side interconnection. During laser engraving, the energy requirements for the potting glue and epoxy glass fiber cloth are different. In order to avoid the metal powder from etching the interconnection pattern remaining in the glass fiber material of the substrate, resulting in the risk of potential leakage or short circuit of the potting body, the excess substrate under the lead needs to be removed.

[0023] The technical solution of the present invention is to improve the design of the suspension lead structure and develop a new structure: the epoxy base material of the substrate is used to partially reinforce the suspension lead. Its structural characteristics are: 0.1-0.2mm of the epoxy base material under the copper lead is retained, and the base material on both sides of the suspension lead is completely removed. The base material reinforcement lead process is adopted to improve the structural strength of the suspension lead, reduce the process difficulty, reduce the processing flow, and improve the yield rate.

[0024] like Figure 1 As shown, the present invention provides a method for manufacturing a POP three-dimensional stacked interconnection substrate, comprising: S101 uses epoxy glass cloth laminate for stacking design, and performs sheet cutting and sheet mapping for each layer of sheets; S102 performs inner layer etching on the thin film, and performs lamination operation on each layer of the thin film to obtain a laminated substrate; S103 performs drilling and hole metallization operations on the substrate to obtain metallized holes; S104 performs pattern transfer and pattern electroplating operations on the substrate; S105 performs alkaline etching and depth control processing on the substrate; S106 controls the laser cutting and degumming operations of substrates after deep processing; S107 performs solder mask coating on the top and bottom surfaces of the substrate according to the design layout, then performs chemical nickel-gold deposition, and finally performs external processing to obtain a POP three-dimensional stacked interconnect substrate. The detailed steps are: Process flow: stacking design → sheet cutting → sheet drawing → inner layer etching → lamination → drilling → hole forming → pattern transfer → pattern electroplating → alkaline etching → controlled depth milling → laser cutting → chemical degumming → silk screen solder mask → chemical nickel gold deposition → appearance processing.

[0025] S1: Layered design The epoxy glass cloth laminate is used for stacking design, the inner core board with a substrate thickness of 0.15mm and a substrate copper thickness of 18um / 18um is used, and 4 1080 type semi-cured sheets and an outer layer of 18um copper foil are used for stacking design. According to the theoretical thickness of the material, the theoretical thickness of the interconnect substrate is calculated to be 0.6mm, and the depth of the suspended lead processing is calculated to be 0.35~0.4mm. The corresponding graphics and CNC processing files are produced according to the design layout. Stacking design such as Figure 2 As shown: S2: Sheet blanking: The L2 / 3 layers are processed using sheets with a substrate thickness of 0.15mm and a copper thickness of 18um, and the L1 and L4 layers are processed using 18um copper foil.

[0026] S3: Sheet drawing: Transfer the pattern from the transfer medium to the sheet. The transfer process requires the positioning and alignment of the pattern and ensures full contact between the transfer medium and the printed board. The sheet drawing process includes the following four steps: Step 1: Clean and roughen the surface of the sheet by sandblasting or chemical micro-etching; Step 2: Remove the transfer medium from the lower carrier, place the transfer medium (film or membrane) and the printed board at the contact part of the guide line, keep them in full contact, and use the squeeze roller to fix the transfer medium on the printed board. Before fixing, you need to use the positioning guide line to align the position of the transfer medium and the printed board; Step 3: Select the film with the corresponding pattern and attach it to the front and back of the sheet, and use the exposure machine to photo-cure the transfer medium; Step 4: Manually peel off the film on the top and bottom of the sheet and let it stand for a while, then crack the surface-cured photosensitive glue according to the area divided by the film pattern and clean it.

[0027] Table 1 CCD exposure machine parameters

[0028] S4: Inner layer etching: Use a special etching device with an etching solution of a certain proportion of components, adjust the solution concentration, temperature and spray pressure to a suitable range, determine the etching speed according to the copper thickness of the thin film, put the thin film covered with the pattern medium into the etching device, and remove the copper foil in the area not covered by the pattern medium by chemical etching to obtain a circuit pattern with neat wire edges. The inner layer etching process includes the following two steps: The first step is to etch the copper surface without anti-corrosion layer protection to make the inner conductive pattern; the second step is to remove the anti-corrosion dry film in the non-effective pattern area on the surface of the thin film.

[0029] Table 218um thickness copper foil etching speed

[0030] S5: Lamination: Use prepreg (a sheet material made of glass fiber impregnated with epoxy resin and then baked to remove the solvent. The resin is in the B stage and has flow properties under the action of temperature and pressure and can quickly solidify and complete bonding) to bond the conductive patterns together under high temperature and high pressure according to the corresponding stacking design requirements. The lamination process includes the following six steps: Step 1: Cut the prepreg into single pieces in a clean and dust-free environment and process the positioning holes; Step 2: Blacken the inner thin sheet that has completed the circuit pattern production to increase the interlayer bonding strength of the inner layer after lamination; Step 3: Use a hot melt machine or a rivet machine to complete the pre-lamination according to the corresponding lamination requirements; Step 4: Perform lamination processing according to the lamination requirements based on the product type; Step 5: Transport the stacked lamination mold to the vacuum laminator through the conveying equipment; Step 6: Call the corresponding lamination program to complete the lamination process.

[0031] S6: Drilling: by special drilling machine, such as Figure 3As shown, according to the design file, a hole with the required aperture size is processed at the specified position of the substrate after lamination. The drilling process includes the following four steps: Step 1: Process the positioning holes on the multilayer board; check the overlap of the inner layer graphics, measure the expansion and contraction values, identify and mark the board direction; Step 2: Use pins to fix the multilayer board to the CNC drilling machine workbench at the positioning hole position; Step 3: Read the CNC drilling file into the CNC drilling machine to perform drilling processing on the multilayer board; Step 4: Read the CNC milling file into the CNC milling machine to perform shape processing on the substrate.

[0032] S7: Hole metallization: Using the deposition of colloidal palladium, the activation of palladium nuclei induces the self-catalytic reaction of chemical copper deposition, depositing a layer of chemical copper on the board surface and hole wall, so that the printed wires of each layer of the interconnect substrate are interconnected to form a network. The hole metallization process includes the following four steps: Step 1: Use a deburring brush to remove burrs at the hole mouth, oxide layer on the board surface, organic pollutants and other impurities, and roughen the surface to enhance the bonding force between the board surface and the chemical copper layer; Step 2: Use chemical plating process on the hole wall of the printed circuit board to deposit a layer of copper film to achieve metallization on the hole wall surface and make the inner layer of each network conductive; Step 3: Electroplate a dense copper layer on the printed circuit board after chemical copper deposition to provide good conductivity and sufficient strength for the metallized holes of the printed circuit board; Step 4: Clean and dry the electroplated printed circuit board.

[0033] S8: Graphic transfer: the method and steps are the same as S3.

[0034] S9: Graphic plating: Graphic plating is a process of selectively forming a coating on the surface of a substrate covered with a graphic dry film by electrolytic deposition. The graphic plating process includes the following two steps: The first step is to plate a copper layer of required thickness on the metallized holes and circuit surfaces; the second step is to plate a tin layer of required thickness on the metallized holes and circuit surfaces.

[0035] S10: Alkaline etching: Use the anti-corrosion properties of dry film / wet film to protect the effective pattern part, and remove the copper surface without anti-corrosion layer protection by etching with alkaline copper chloride solution. The alkaline etching process includes the following three steps: The first step is to remove the anti-plating dry film in the non-effective pattern area on the surface of the substrate; the second step is to etch the copper surface without anti-corrosion layer protection to make the outer conductive pattern; the third step is to remove the tin protective layer on the conductive circuit.

[0036] S11: Controlled depth processing: Use a dedicated CCD controlled depth milling machine to retrieve the corresponding depth control file and perform controlled depth processing of the substrate in the hanging lead area according to the stacking design theory. The controlled depth milling process includes the following three steps: The first step: make a high-precision depth-controlled special base plate; the second step: before the depth-controlled processing, measure and calibrate the worktable of the CNC milling machine, and use the high-precision depth-controlled special base plate to ensure that the flatness of the table is controlled within ±30μm before processing the product; the third step is to mill and cut the entire board into a single board, and then use the non-metallized holes in the single board for positioning and installation, and perform depth-controlled thinning processing on the bottom substrate of the hanging lead slot.

[0037] High-precision depth control single plate positioning and depth control table structure such as Figure 4 As shown, the product depth control effect is as follows Figure 5 shown.

[0038] S12: Laser cutting: Laser cutting uses a focused high-power, high-density laser beam to irradiate the plate, causing the irradiated material to be rapidly ablated, melted, and vaporized. At the same time, the molten material is blown away by a high-speed airflow coaxial with the beam, thereby cutting the epoxy substrate material between the suspended leads. The laser cutting process includes the following three steps: Step 1: Place the substrate in the relative position of the laser cutting work surface according to the guide line; Step 2: Read the laser cutting file into the laser processing equipment, locate the substrate through the MARK point recognition system and perform the first trial processing of laser cutting; Step 3: Apply the laser parameters determined by the first trial processing to the remaining substrates in the same batch for batch processing.

[0039] The laser cutting effect on the front and back sides of the hanging lead area is as follows Figure 7 and Figure 8 Shown S13: Chemical debonding: The carbonized substrate on the surface of the epoxy substrate after laser cutting is removed by the erosion of potassium permanganate. The chemical debonding process includes the following two steps: The first step is to load the interconnect substrate single board onto the designated hanger of the hole metallization production line; the second step is to start the debonding program to perform the debonding operation.

[0040] S14: Silkscreen solder mask: Solder mask is applied on the surface of the top and bottom layers of the substrate according to the design layout. The silkscreen solder mask process includes the following six steps: Step 1: Make a solder mask graphic printing template negative film; Step 2: Place the interconnected substrate in the relative size position of the screen printer through the guide line and align it completely; Step 3: Use mechanical pressure to print the solder mask ink through the screen on the surface of the substrate; Step 4: Position and fix the prepared printed negative film to the substrate through the positioning guide holes around the substrate, and keep it in full contact, and use an exposure machine to photo-cure the solder mask medium; Step 5: Put the exposed substrate with solder mask into the solder mask developer for development, and remove the unexposed solder mask layer covered by the negative film; Step 6: Perform curing according to the curing parameters of the solder mask material.

[0041] S15: Chemical nickel-gold deposition: deposit a nickel layer of appropriate thickness on the pad of the interconnect substrate, and then replace a gold layer of a certain thickness on the nickel layer to provide ultra-high flatness of the pad surface during welding, and form a protective layer on the pad surface and sidewalls to facilitate subsequent various lap welding or metal wire welding. The chemical nickel-gold deposition process includes the following three steps: Step 1: Use a sandblaster to remove the oxide layer, organic pollutants and other impurities on the board surface, and roughen the surface to enhance the bonding strength between the board surface and the chemical nickel layer; Step 2: Deposit a chemical nickel-gold layer on the exposed copper wire and pad area of ​​the substrate to protect the wire / pad surface and side walls; Step 3: Clean and dry the processed substrate product.

[0042] S16: Shape processing: According to the requirements of the drawing, the base plate is milled into the shape required by the design. The shape processing process includes the following three steps: Step 1: Import the CNC milling file into the computer dedicated to shape processing, transfer it into the equipment computer and read it out; Step 2: Determine the direction of the board according to the CNC milling graphics, and fix the board to be processed on the workbench; Step 3: Open the file, set the tool type and diameter required for milling; Step 4: Start the equipment to complete the processing of the substrate shape.

[0043] Although the embodiments of the present invention are described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments and application fields, and the above-mentioned specific embodiments are only illustrative and instructive, rather than restrictive. Under the guidance of the specification, a person skilled in the art can also make many forms without departing from the scope of protection of the claims of the present invention, all of which belong to the scope of protection of the present invention.

Claims

1. A method for manufacturing a POP three-dimensional stacked interconnect substrate, characterized in that: include: Use epoxy glass cloth laminates to design the stack-up, and perform sheet cutting and sheet mapping for each layer; Performing inner layer etching on the thin film, and laminating each layer of the thin film to obtain a laminated substrate; Performing drilling and hole metallization operations on the substrate to obtain metallized holes; Perform pattern transfer and pattern electroplating operations on substrates; Perform alkaline etching and depth control on the substrate; Control the laser cutting and degumming operations of substrates after deep processing; Solder mask coating is applied on the surface of the top and bottom layers of the substrate according to the design layout, followed by chemical nickel-gold deposition, and finally external shape processing to obtain a POP three-dimensional stacked interconnect substrate.

2. The method for manufacturing a POP three-dimensional stacked interconnect substrate according to claim 1, characterized in that: The specific steps of thin-section mapping are: Clean and roughen the surface of the sheet by sandblasting or chemical micro-etching; Remove the transfer medium from the lower carrier, place the transfer medium and the printed board at the contact part of the guide line, keep them in full contact, and use the squeezing roller to fix the transfer medium on the printed board. Before fixing, use the positioning guide line to align the position of the transfer medium and the printed board; Select the negative film with the corresponding pattern and attach it to the front and back of the sheet, and use an exposure machine to perform light curing on the transfer medium; After peeling off the negative film on the top and bottom layers of the sheet and letting it stand for a period of time, the photosensitive adhesive solidified on the surface is decomposed according to the areas divided by the negative film pattern and cleaned.

3. The method for manufacturing a POP three-dimensional stacked interconnect substrate according to claim 1, characterized in that: The specific steps of inner layer etching are: Etch the copper surface without anti-corrosion layer protection to make inner conductive pattern; Remove the dry resist film from the non-effective pattern area on the surface of the thin film.

4. The method for manufacturing a POP three-dimensional stacked interconnect substrate according to claim 1, characterized in that: The specific steps of the lamination operation are: Cut the prepreg into individual pieces and process the positioning holes in a clean and dust-free environment; The inner layer sheet that has been completed with circuit pattern production is blackened to increase the bonding strength between the inner layers of the board after lamination; Use hot melt machine or riveting machine to complete pre-stack-up according to corresponding stacking requirements; Carry out lamination processing according to the requirements of pressed lamination based on product types; The stacked pressing molds are transported to the vacuum laminator through a conveying device; Retrieve the corresponding pressing program to complete the pressing process.

5. The method for manufacturing a POP three-dimensional stacked interconnect substrate according to claim 1, characterized in that: The specific steps of drilling are: Process positioning holes on multi-layer boards, check the overlap of inner layer patterns, measure expansion and contraction values, and identify and mark board directions; Fix the multilayer board to the CNC drilling machine table with pins at the locating holes; Read the NC drilling file into the NC drilling machine to drill holes on the multilayer board The CNC milling file is read into the CNC milling machine to perform shape processing on the substrate.

6. The method for manufacturing a POP three-dimensional stacked interconnect substrate according to claim 1, characterized in that: The specific steps of hole metallization operation are: Use a deburring brush to remove burrs at the hole, oxide layer on the board surface, organic pollutants and other impurities, and roughen the surface to enhance the bonding strength between the board surface and the chemical copper layer; A layer of copper film is deposited on the hole wall of the printed circuit board using chemical plating technology to achieve metallization of the hole wall surface and make the inner layer of each network conductive; Electroplating a dense copper layer on the printed circuit board after chemical copper deposition provides good conductivity and sufficient strength for the metallized holes of the printed circuit board; Clean and dry the printed circuit board after primary electroplating.

7. The method for manufacturing a POP three-dimensional stacked interconnect substrate according to claim 1, characterized in that: The specific steps of alkaline etching are: Remove the anti-plating dry film from the non-effective pattern area on the surface of the substrate; Etch the copper surface without anti-corrosion layer protection to make the outer conductive pattern; Remove the tin protective layer on the conductive circuit.

8. The method for manufacturing a POP three-dimensional stacked interconnect substrate according to claim 1, characterized in that: The specific steps of deep processing are: Make a special base plate for high-precision depth control; Before depth control processing, the CNC milling machine work table is measured and calibrated, and a high-precision depth control special base plate is used to ensure that the table surface flatness is controlled within ±30μm before processing the product; The whole board is milled and processed into a single board, and then the non-metallized holes in the single board are used for positioning and installation, and the bottom substrate of the hanging lead is grooved and depth-controlled and thinned.

9. The method for manufacturing a POP three-dimensional stacked interconnect substrate according to claim 1, characterized in that: The specific steps for applying solder mask coating on the surface of the top and bottom layers of the substrate according to the design layout are as follows: Make solder mask pattern printing template negative film; Place the interconnect substrate in the relative size position of the screen printer through the guide line and align it perfectly; The solder mask ink is printed on the substrate surface through the screen by mechanical pressure. Position and fix the prepared printed film to the substrate through the positioning guide holes around the substrate, keep them in full contact, and use an exposure machine to perform photocuring on the solder resist medium; The exposed substrate with the solder mask is placed in a solder mask developer for development, and the unexposed solder mask layer shielded by the film is removed; And perform curing according to the curing parameters of the solder resist material.

10. A POP three-dimensional stacked interconnect substrate, characterized in that: The method for manufacturing a POP three-dimensional stacked interconnect substrate according to any one of claims 1 to 9 is used, wherein 0.1 to 0.2 mm of the epoxy base material below the copper lead is retained, and the base material on both sides of the suspended lead is completely removed.

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